Escherichia coli ( ESH-ə-RIK-ee-ə KOH-ly) is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus Escherichia that is commonly found in the lower intestine of warm-blooded organisms. Most E. coli strains are harmless, but some serotypes such as EPEC, and ETEC are pathogenic and can cause serious food poisoning in their hosts, and are occasionally responsible for food contamination incidents that prompt product recalls. Most strains are part of the normal microbiota of the gut and are harmless or even beneficial to humans (although these strains tend to be less studied than the pathogenic ones). For example, some strains of E. coli benefit their hosts by producing vitamin K2 or by preventing the colonization of the intestine by pathogenic bacteria. These mutually beneficial relationships between E. coli and humans are a type of mutualistic biological relationship — where both the humans and the E. coli are benefitting each other. E. coli is expelled into the environment within fecal matter. The bacterium grows massively in fresh fecal matter under aerobic conditions for three days, but its numbers decline slowly afterwards.
Probiotics are live microorganisms promoted with claims that they provide health benefits when consumed, generally by improving or restoring the gut microbiota. Probiotics are considered generally safe to consume, but may cause bacteria-host interactions and unwanted side effects in rare cases. There is some evidence that probiotics are beneficial for some conditions, but there is little evidence for many of the health benefits claimed for them.
Lactobacillus acidophilus is a rod-shaped, Gram-positive, homofermentative, anaerobic microbe first isolated from infant feces in the year 1900. The species is commonly found in humans, specifically the gastrointestinal tract and oral cavity as well as various fermented foods such as fermented milk or yogurt. The species most readily grows at low pH levels, and has an optimum growth temperature of 37 °C. Certain strains of L. acidophilus show strong probiotic effects, and are commercially used in dairy production. The genome of L. acidophilus has been sequenced.
Gut microbiota, gut microbiome, or gut flora are the microorganisms, including bacteria, archaea, fungi, and viruses, that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the gut microbiota. The gut is the main location of the human microbiome. The gut microbiota has broad impacts, including effects on colonization, resistance to pathogens, maintaining the intestinal epithelium, metabolizing dietary and pharmaceutical compounds, controlling immune function, and even behavior through the gut–brain axis.
Cecotropes are a nutrient filled package created in the gastointestinal (GI) tract, expelled and eaten by rabbits and guinea pigs to get more nutrition out of their food. The first time through the GI tract, small particles of fiber are moved into the cecum, where microbes ferment them. This creates useable nutrients which are stored and expelled in cecotropes. The cecotropes are eaten and the nutrients are absorbed in the small intestine.
Dysbiosis is characterized by a disruption to the microbiome resulting in an imbalance in the microbiota, changes in their functional composition and metabolic activities, or a shift in their local distribution. For example, a part of the human microbiota such as the skin flora, gut flora, or vaginal flora, can become deranged, with normally dominating species underrepresented and normally outcompeted or contained species increasing to fill the void. Similar to the human gut microbiome, diverse microbes colonize the plant rhizosphere, and dysbiosis in the rhizosphere, can negatively impact plant health. Dysbiosis is most commonly reported as a condition in the gastrointestinal tract or plant rhizosphere.
Skin flora, also called skin microbiota, refers to microbiota that reside on the skin, typically human skin.
Microbiology is the scientific study of microorganisms, those being of unicellular (single-celled), multicellular, or acellular. Microbiology encompasses numerous sub-disciplines including virology, bacteriology, protistology, mycology, immunology, and parasitology.
Pediococcus acidilactici is a species of Gram-positive cocci that is often found in pairs or tetrads. P. acidilactici is a homofermentative bacterium that can grow in a wide range of pH, temperature, and osmotic pressure, therefore being able to colonize the digestive tract. It has emerged as a potential probiotic that has shown promising results in animal and human experiments, though some of the results are limited. They are commonly found in fermented vegetables, fermented dairy products, and meat.
Bifidobacterium is a genus of gram-positive, nonmotile, often branched anaerobic bacteria. They are ubiquitous inhabitants of the gastrointestinal tract though strains have been isolated from the vagina and mouth of mammals, including humans. Bifidobacteria are one of the major genera of bacteria that make up the gastrointestinal tract microbiota in mammals. Some bifidobacteria are used as probiotics.
Wageningen Academic Publishers is a publishing company in the field of life sciences that publishes scientific journals as well as monographs, textbooks, and proceedings. The company was founded in 2002 as successor of Wageningen Pers. The company publishes books in the fields of animal, food, social, plant, and environmental sciences. In 2022 Wageningen Academic Publishers was purchased by Brill Publishers.
Lacticaseibacillus paracasei (commonly abbreviated as Lc. paracasei) is a gram-positive, homofermentative species of lactic acid bacteria that are commonly used in dairy product fermentation and as probiotic cultures. Lc. paracasei is a bacterium that operates by commensalism. It is commonly found in many human habitats such as human intestinal tracts and mouths as well as sewages, silages, and previously mentioned dairy products. The name includes morphology, a rod-shaped bacterium with a width of 2.0 to 4.0μm and length of 0.8 to 1.0μm.
The altered Schaedler flora (ASF) is a community of eight bacterial species: two lactobacilli, one Bacteroides, one spiral bacterium of the Flexistipes genus, and four extremely oxygen sensitive (EOS) fusiform-shaped species. The bacteria are selected for their dominance and persistence in the normal microflora of mice, and for their ability to be isolated and grown in laboratory settings. Germ-free animals, mainly mice, are colonized with ASF for the purpose of studying the gastrointestinal (GI) tract. Intestinal mutualistic bacteria play an important role in affecting gene expression of the GI tract, immune responses, nutrient absorption, and pathogen resistance. The standardized microbial cocktail enabled the controlled study of microbe and host interactions, role of microbes, pathogen effects, and intestinal immunity and disease association, such as cancer, inflammatory bowel disease, diabetes, and other inflammatory or autoimmune diseases. Also, compared to germfree animals, ASF mice have fully developed immune system, resistance to opportunistic pathogens, and normal GI function and health, and are a great representation of normal mice.
The human milk microbiota, also known as human milk probiotics (HMP), encompasses the microbiota–the community of microorganisms–present within the human mammary glands and breast milk. Contrary to the traditional belief that human breast milk is sterile, advancements in both microbial culture and culture-independent methods have confirmed that human milk harbors diverse communities of bacteria. These communities are distinct in composition from other microbial populations found within the human body which constitute the human microbiome.
Postbiotics - also known as metabiotics, biogenics, or simply metabolites - are soluble factors, secreted by live bacteria, or released after bacterial lysis providing physiological benefits to the host.
Lacto-N-tetraose is a complex sugar found in human milk. It is one of the few characterized human milk oligosaccharides (HMOs) and is enzymatically synthesized from the substrate lactose. It is biologically relevant in the early development of the infant gut flora.
Escherichia coli (AIEC) NC101 is a mouse isolate, serotype O2:H6/41, that is pro-carcinogenic, adherent-invasive (AIEC), probiotic strain of Escherichia coli, a species of bacteria that thrives in the intestines of mammals. NC101 has also been identified as a nicotinic acid (NA) auxotroph, a pathobiont, which is an organism that is harmful under certain circumstances, and is an important, relevant model organism that demonstrates how susceptible individuals may produce inappropriate immune responses to seemingly benign intestinal E. coli.
Seed Health, popularly known as Seed, is an American health and life science company, most known for developing probiotics. Founded in 2015 by Ara Katz and Raja Dhir, Seed was founded to "use bacteria to improve human and environmental health". The company's main product, the probiotic DS-01, is sold direct to consumer, forgoing traditional brick-and-mortar retail.
Bifidobacterium adolescentis is an anaerobic species of bacteria found in the gastrointestinal tracts of humans and other primates. It is one of the most abundant and prevalent Bifidobacterium species detected in human populations, especially in adults.
